How to delete Accounts created in the last 7 days in Salesforce?

Select id from TechM__c where CreatedDate <= 2016-11-15T00:00:00Z Select id from TechM__c where DAY_ONLY(CreatedDate) <= 2016-11-15Select id from TechM__c where CreatedDate <= YESTERDAY Select id from TechM__c where CreatedDate = TODAY